Dartmouth in Need of More Math Puzzlers

From: George Wolford

I teach graduate statistics at Dartmouth College. Whenever the puzzler is mathematical, I assign it as homework (saves me having to think something up). You all could do me a big favor by using more mathematical puzzles. Oh, and by the way, could you send the answers in advance? If I'm going to assign it as homework, it's easier to grade if I know the answer.